Finding the Fourth Proportional to 261,196.49, 392,254.14 and 257,456.72

Step by Step Solution

1. Step 1: Write the proportion equation
   261,196.49 : 392,254.14 = 257,456.72 : x
2. Step 2: Convert to fraction form
   261,196.49/392,254.14 = 257,456.72/x
3. Step 3: Cross multiply
   261,196.49x = 392,254.14 × 257,456.72
4. Step 4: Simplify right side
   261,196.49x = 100,988,464,290.82
5. Step 5: Solve for x
   x = 100,988,464,290.82/261,196.49
6. Step 6: Final answer
   x = 386,637.91